In its broadest aspect, this invention relates to attachments which controllably introduce fluid soluble material into a pipeline fluid stream. Applications for such devices include the chlorination of swimming pools, water purification processes, insecticide distribution systems, and fertilizer application systems. The production and distribution of plant fertilizer in solid form such as in pellets or powders is common practice even though a liquid solution is required to benefit the plant life. It makes economic sense to distill the essence of the substance into a light weight solid form for shipping and selling and to leave the final mixing with water to the final user. Often the dry pellets are simply spread over the ground area and followed with a general watering or sprinkling to dissolve the pellets and provide plant useable nutrient. This process inevitably leads to grossly uneven distribution of the fertilizer causing damage to plants in some areas and insufficient nutrient in others. Also the plant leaves, which are capable of absorbing liquid nutrients, are not fed by this process. In addition, a heavy rain can wash away large quantities of the solid nutrient before it has a chance to dissolve and be absorbed by the plant roots. This not only starves the plants but, even worse, it contaminates the geographic water drainage basin endangering marine life and possibly polluting human water sources.
Another approach often used is to manually mix batches of liquid fertilizer from the dry raw ingredients prior to application which then usually must also be done manually. The dependence on the user to prepare the solution to its proper concentration as well as the considerable inconvenience make this approach both unreliable as well as impractical.